Side core locking mechanism for die casting machine



A. F. BAUER Sept. 23, 1969 SIDE CORE LOCKING MECHANISM FOR DIE CASTING MACHINE Filed Aug. 12, 1966 5 Sheets-Sheet 1 ATTYE.

INVENTOR.

, ALFRED f." BA UER.

Sept. 23, 1969 A. F. BAUER 3,468,367

SIDE CORE LOCKING MECHANISM FOR DIE CASTING MACHINE Filed Aug. 12, 1966 3 Sheets-Sheet 2 AL FREE 2? B2: U32

.ATTYS.

A. F. BAUER Sept. 23, 1969 SIDE CORE LOCKING MECHANISM FOR DIE CASTING MACHINE Filed Aug. 12, 1966 3 Sheets-Sheet INVNTOR: ALFRED F BA HER.

ATTYS.

United States Patent U.S. Cl. 164-340 Claims ABSTRACT OF THE DISCLOSURE A core operating mechanism for a die casting machine having a stationary plate and a sliding plate. A rigid frame having opposed receiving seats is mounted on the sliding plate between the stationary and sliding plates. A core slide is mounted on the frame and is reciprocated by a cylinder which is operatively connected between the frame and the core slide. A lock arm having opposed outer ends is pivotally mounted on the core slide. A cylinder driven rack and pinion is connected to the lock arm and is effective to move the outer ends of the lock arm ir 1to and out of locking engagement with the frame receiving seats.

This invention relates to a die casting machine and is particularly directed to a mechanism for locking side cores in place in a die.

Side cores in die casting machines are conventionally moved into and out of position by hydraulic cylinders and various attempts have been made to lock them in place by locking the hydraulic circuit. The cores and the slides that carry them are also sometimes moved into and out of position by mechanical means and in these instances locking has been attempted by making an extension on the cover die that will seat over the core slide when the machine is closed. This latter expedient has many undesirable results. Since the cores are subjected to the full pressure imposed on the die casting metal, which may be several thousand pounds per square inch, and since a core displacement of only a few thousandths of an inch may be intolerable in the sense that it may result in a defective part, locking the cores in a positive manner is highly desirable. The locking forces resulting from a locked hydraulic circuit are frequently inadequate to prevent displacement, and locking the cores and core slides by a cover die extension has often resulted in destruction of the die parts.

The present invention provides a locking mechanism which, after the cores have been moved into place in the die by a conventional hydraulic cylinder, interposes a positive wedge lock between the core slide and the adjacent rigid machine elements. The slide is thus effectively prevented from moving and the parts of the hydraulic system are relieved of any load resulting from pressure on the inner ends of the cores.

The invention is further characterized by a simple and effective means to move the wedge lock into and out of position and to break its frictional engagement with the adjacent machine parts so that the operation can be positively and rapidly accomplished.

Where cores are used on each side of a die the mechanism is duplicated on the two sides of the machine. If the cores are to be inserted in the die only from one side then, obviously, only one core slide and locking mechanism will be required.

A preferred embodiment of the invention is shown in the accompanying drawings, in which:

FIGURE 1 is a side elevational view, with parts broken away, of a die casting machine incorporating the present invention, the machine elements being shown with the die in open position in full lines and certain of the elements being shown in dotted line position to indicate the closed position of the die and of the die closing parts;

FIG. 2 is a section on line 22 of FIG. 1 with the cores in a pulled position;

FIG. 3 is a section on line 33 of FIG. 1 with the cores in the inner position and the parts locked in place;

FIG. 4 is a fragmentary view of the parts shown in FIG. 3 with the wedge lock swung to its unlocked position;

FIG. 5 is a section on line 5-'5 of FIG. 3 with the wedge lock in locked position and shown in dotted lines when swung to its unlocked position as shown in FIG. 4;

FIG. 6 is a fragmentary sectional view on line 5-5 of FIG. 4 with the parts shown in position in which the wedge lock is initially released; and

FIG. 7 is a fragmentary sectional view taken on line 77 of FIG. 6.

Referring to the drawings, and particularly to FIG. 1, the present invention is shown applied to a die casting machine of conventional construction including a base 10 on which a rear plate 11 is adjustably mounted. A stationary front plate 12 is fixed to the base and intermediate the front and rear plates is a sliding plate 13 actuated by a conventional toggle mechanism 14 which, in turn, is moved by a closing cylinder 15. Machine tie bars 16 connect the front and rear plates 12 and 11 and serve as guides for the sliding plate 13. At the front of the machine there is a conventional shot cylinder 17, a shot sleeve 18 and a pedestal 19 to support the shot cylinder. A cover die 20 is fixed in the usual manner to the front plate 12 and an ejector die 21 cooperates therewith.

The present invention includes a relatively massive rigid core and die support frame 22 fixed to the sliding plate 13. The heavy frame 22, as indicated in FIG. 2, carries opposite core slides 23. In the present instance cores are used on each side of the die. The core slide 23 is mounted for reciprocation on the frame 22 and is guided on bars 24. The slide is actuated by a cylinder 25 carried on the frame and having a piston rod 26 extending therefrom into operable connection with the slide 23.

A stub shaft 28 is aligned with the piston rod 26 and a wedge lock 29 is rotatably mounted on the stub shaft. The wedge lock 29 comprises an upper arm 30 and a lower arm 31. The wedge lock 29 is journaled to be moved into an engaged position and into an inoperative position with respect to upper and lower seats 32 formed in the frame 22. The locking surfaces 33 of seats 32 engage the extremities of the upper and lower arms 30 and 31 when the latter are moved into locking position to lock the core slide 23 against outward movement relative to the frame 22.

In the preferred embodiment of the invention the wedge lock 29 is swung into and out of locking position by a pinion 34 operatively connected to the wedge lock and engaging a rack 35 that is actuated by a rack cylinder 36. The rack is guided in its reciprocating movements by a suitable rack guide 37, and the movement of the rack is controlled by a valve 38 by which fluid is admitted to one end or the other of the rack cylinder 36.

One arm of the wedge lock, the lower arm 31 in the instance shown, is provided with a nose extension 39. When the lock is in the engaged or locked position as shown in FIG. 5, the nose extension 39 abuts one arm of a bell crank lever 40 pivoted at 41. An extended operating arm of the bell crank is designated 43 and in the locked position this arm overlies a rod abutment 44 carried on the end of a piston rod 45 extending from a double-acting actuating cylinder 46. Operating fluid is admitted to or exhausted from cylinder 46 by a control valve 47. 2 s

When the wedge lock is in its engaged position and after pressure of a casting operation has been imposed thereon as hereinafter described, it is difficult to cause the parts to release and the unlocking action of the cylinder 46 is required to impart an initial disengaging motion to the wedge lock as shown in FIG. 6. As there indicated the piston rod of the unlocking cylinder moves the bell crank in a counterclockwise direction and thus causes the bell crank to engage the nose extension 39 of the wedge lock to move the latter slightly away from its engaged position. Thereafter, the force of the rack cylinder 36 is adequate to complete the unlocking motion by retraction of the rack 35 and a clockwise movement (in FIG. 6) of the pinion 34.

The operation of the machine comprising the parts so far described can best be followed by reference to the drawings which show the operation sequentially. In FIG- URE 1 of the drawings the machine is shown in full lines in its open position and with the wedge lock 29 disengaged. FIGURE 2 also shows the parts in this position and it can be seen that the cores 27 are withdrawn from the ejector die 21 and the core slides 23 are retracted.

FIGURE 3 shows a section through the machine in the direction of the ejector die 21 with the parts in closed and locked position. It will be seen from this figure that the core slides 23 have been moved forwardly by their actuating cylinders 25 and the piston rods 26 are in their extended positions. The cores 27 are thus inserted in operating position in the ejector die 21.

As can be seen also from FIGURE 3 the wedge lock 29 has been swung to its locked position. The sequence of the operation by which the wedge lock is moved into and out of engagement with the frame 22 can best be followed from FIG. 5.

FIG. shows in dotted lines the position occupied by the wedge lock 29 when open and in a position for the core slide 23 to be retracted. In full lines this figure shows the wedge lock in its engaged position against the locking surfaces 33. The operation of moving the wedge lock 29 into locked position has been performed by admitting fluid into the rack cylinder 36 to cause the rack 35 to move to the left in FIG. 5 and to rotate the wedge lock 29 in a counterclockwise direction.

With the parts as shown in FIGURES 3 and 5 a die casting shot can be made with metal being forced from the shot sleeve 18 by actuation of the shot cylinder 17 in the usual manner. The molten metal enters the die under very high pressure, frequently in the order of 10,000 p.s.i., and this pressure is imposed on the projected end area of the cores 27. The pressure, of course, tends to displace the cores and this displacement force is resisted by the locked core slide 23 and is taken through the wedge lock 29 to the rigid frame 22. Any displacement of the cores is thereby effectively resisted.

After the completion of the shot it will be found that the wedge lock 29 has been pushed into a full frictional engagement with the locking surfaces 33. While the rack cylinder 36 may in some instances be sufficiently powerful to disengage the wedge lock, the present invention provides a simple and efiective mechanism shown in FIGS. 5 and 6 for this purpose. The unlocking cylinder 46 is actuated by moving the control valve 47 to a position such that pressure is imposed on the piston rod 45 beneath the piston and thus moving the rod abutment 44 against the extended operating arm 43 of the bell crank lever 40. This moves the parts to the position shown in FIG. 6, and it can be seen in this figure that the bell crank has moved against the nose 39 and has moved the wedge lock to a partially unlocked position, free from the wedging locking surfaces 33. Thereafter, the rack cylinder is sutficiently powerful to complete the unlocking movement of the wedge lock and to move it to a point where it can be retracted along with the slide by the core actuating cylinder 25 to move all of the parts back to the position shown in FIG. 2.

While the invention has been disclosed in conjunction with a specific form and disposition of the parts, it should be expressly understood that numerous modifications and changes may be made therein without departing from the scope of the appended claims.

I claim:

1. A core operating mechanism for a die casting machine having a stationary plate and a sliding plate comprising, in combination, a rigid frame defining a frame receiving seat mounted on said sliding plate between said stationary plate and said sliding plate, a core carrying slide mounted for reciprocation on said frame from a first position in which cores fixed on said slide are withdrawn from the cavity of an associated die and a second position in which the cores are inserted in the die cavity, means carried by said frame and operably connected to said slide for reciprocating said slide between said first and second positions, lock means operably mounted on said slide, said lock means including a lock arm pivotally mounted on said slide, said lock arm having an outer end complementary with said frame receiving seat, and means to move said outer end of said lock arm into engagement with said frame receiving seat to lock said slide against movement relative to said frame and the cores relative to the die cavity independent of any force exerted by said slide reciprocating means, said last means being operable to move said lock means out of its engaged position to allow movement of said slide relative to said frame and withdrawal of the cores from the die cavity.

2. A core operating mechanism for a die casting machine in accordance with claim 1 in which said outer end of said lock has a wedging engagement with said frame when said outer end is engaged with said frame receiving seat.

3. A core operating mechanism for a die casting machine in accordance with claim 1 and wherein said means for moving said outer end of said lock arm includes a rack and pinion to swing said lock arm into and out of engaged position.

4. A core operating mechanism for a die casting machine in accordance with claim 1 and means engageable with said lock arm when in engaged position to impart an initial releasing movement thereto.

5. A core operating mechanism for a die casting machine in accordance with claim 1, wherein said frame defines two opposed receiving seats, said lock arm having opposed outer ends, each of said opposed outer ends complementary with a respective one of said frame receiving seats.

References Cited UNITED STATES PATENTS 1,318,380 10/1919 I-Iazelett l64340 2,115,590 4/ 1938 Ryder.

2,254,295 9/1941 Kohl et al. 164340 X 3,165,796 1/1965 McDonald 164340 X FOREIGN PATENTS 384,194 1965 Switzerland.

F I. SPENCER OVERHOLSER, Primary Examiner R. D. BALDWIN, Assistant Examiner US. Cl. X.R. 

